DS1972-F3 MAXIM [Maxim Integrated Products], DS1972-F3 Datasheet - Page 23

• Manufacturer Part Number: DS1972-F3
• Description: 1024-Bit EEPROM iButton
• Manufacturer: MAXIM [Maxim Integrated Products]

MEMORY FUNCTION EXAMPLE
Write to the first 8 bytes of memory page 1. Read the entire memory.
With only a single DS1972 connected to the bus master, the communication looks like this:
MASTER MODE
RX
RX
RX
RX
RX
RX
RX
RX
RX
RX
RX
RX
RX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
¾
DATA (LSB FIRST)
<2 bytes CRC16\>
<2 bytes CRC16\>
<1-Wire idle high>
<144 data bytes>
<8 data bytes>
<8 data bytes>
(Presence)
(Presence)
(Presence)
(Presence)
(Presence)
(Reset)
(Reset)
(Reset)
(Reset)
(Reset)
CCh
CCh
AAh
CCh
AAh
CCh
0Fh
F0h
20h
00h
20h
00h
07h
55h
20h
00h
07h
00h
00h
23 of 23
Reset Pulse
Presence Pulse
Issue “Skip ROM” command
Issue “Write scratchpad” command
TA1, beginning offset = 20h
TA2, address = 0020h
Write 8 bytes of data to scratchpad
Read CRC to check for data integrity
Reset Pulse
Presence Pulse
Issue “Skip ROM” command
Issue “Read scratchpad” command
Read TA1, beginning offset = 20h
Read TA2, address = 0020h
Read E/S, ending offset = 111b, AA, PF = 0
Read scratchpad data and verify
Read CRC to check for data integrity
Reset Pulse
Presence Pulse
Issue “Skip ROM” command
Issue “Copy scratchpad” command
TA1
TA2
E/S
Wait t
complete
Read copy status, AAh = success
Reset Pulse
Presence Pulse
Issue “Skip ROM” command
Issue “Read Memory” command
TA1, beginning offset = 00h
TA2, address = 0000h
Read the entire memory
Reset Pulse
Presence Pulse
PROGmax
for the copy function to
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